Musannaf Ibn Abi Shayba 18:1130

Abu Bakr narrated to us, he said: Ibn ‘Ulayyah narrated to us, from al-Hajjaj ibn Abi ‘Uthman, he said: Abu Raja’, the freed slave of Abu Qilabah, narrated to me, from Abu Qilabah, that ‘Umar ibn ‘Abd al-‘Aziz brought his throne out to the people one day, then he gave them permission, so they entered upon him. He said: "What do you say regarding the *Qasamah* (oath-based blood money/retaliation)?" The people remained silent. Then they said: "We say that the *Qasamah* is a right by which retaliation is taken, and the Caliphs have taken retaliation by it." He said: "What do you say, O Abu Qilabah?" And he set me up before the people. I said: "O Commander of the Faithful, you have with you the nobles of the Arabs and the leaders of the armies. Have you considered if fifty of them were to testify against a man in Homs that he had stolen, and they did not see him [doing it], would you cut off his hand?" He said: "No." I said: "And the Messenger of Allah (peace and blessings of Allah be upon him) never killed anyone at all except for one of three reasons: a man who kills for his own crime, or a man who commits adultery after having been married, or a man who wages war against Allah and His Messenger and apostatizes from Islam."